Antioxidant and alpha‐amylase inhibitory potentials of Cocos nucifera husk

Concoctions containing extract from Cocos nucifera husk fiber are used in Nigeria by traditional medicine practitioners for management of diabetes and its associated complications. Preliminary antidiabetic study was designed to validate the folkloric usage of the plant extract. Dried coconut husk fiber was pulverized and extracted with methanol, followed by partitioning of the methanolic extract in ethyl acetate. Phenolic content, radical scavenging activity and antioxidant capacity as well as inhibitory effects of C. nucifera methanolic (CN‐M) extract and its ethyl acetate (CN‐E) fraction on pancreatic α‐amylase and lipid peroxidation were determined. Total phenolic content and antioxidant capacity of CN‐E fraction were significantly higher than that of CN‐M extract, whereas there was no significant difference in their ability to scavenge free radicals. The CN‐E fraction also exhibited higher in vitro and in vivo inhibitory effects on α‐amylase activity and lipid peroxidation; reducing blood glucose level within 5 days following intraperitoneal administration of the C. nucifera extract to alloxan‐induced hyperglycemic rats. The phenolic‐rich extracts from coconut husk can be further explored as nutraceutical supplement in food formulation for diabetic patients.